SCALE (1) A small thin flake, plate or shell. The word. in O. Eng. is sceale, so bean-sceale, the husk or pod of a bean; cognate forms are found in Ger. Schale, O.H.G. Scale, from which the O. Fr. escale, modern gcale, is borrowed. The ultimate root is seen in the closely allied " shell," and also in skull, scalp, shale and skill, and means to peel off, separate, divide. The word is used specifically (1) in botany, of the rudimentary flake-like leaf forming the covering of the leaf-buds of deciduous trees and of the bracts of the cone in conifers; (2) in zoology, of the flat, hard structures of the epidermis or exoskeleton in fishes, reptiles. Thus in ichthyology the various types of scales are classed as cycloid (Gr. abaor, circle), where the growth is in layers, equally from the anterior and posterior edges; ctenoid (Gr. KTIv, comb), where the posterior edge is toothed; ganoid (Gr. yavor, shining), with a hard enamelled surface and usually rhomboidal in shape, and placoid (Gr. irXii , tablet), as in the ossified papillae of the cutis of the shark. In reptiles the term is applied to the structures which form the covering of the true reptiles, snakes and lizards. In entomology the downy covering
au-apended cradle baaf
of the wings of lepidoptera consists of minute scales, really modifications of hairs, covered with fine lines, giving the bright colours. Another form in O. Eng. scale is found glossing the Lat. lanx, flat bowl or dish, and is thus used of the dishes or cups of a balance (bilanx), the instrument itself being also called " scales."
2. Properly a ladder, flight of steps, now only used in the derived " scaling ladder." The word is derived from the Lat. scala (originally scandla, from scandere to climb). There are many transferred senses of the word, e.g. the distinguishing marks for purposes of measurement on a rule or other measuring instrument; hence a graduated measure or a system of proportional measurement or numeration, and particularly, in music, a series of tones at definite standard intervals (see HARMONY, MUSICAL NOTATION).